Investigation of the interaction between (−)‐epigallocatechin‐3‐gallate with trypsin and α‐chymotrypsin

Abstract

Tea polyphenol (TP) inhibits digestive enzymes and reduces food digestibility. To explore the interaction between TP with digestive enzymes, bindings of -epigallocatechin-3-gallate (EGCG) to trypsin and a-chymotrypsin were studied in detail using fluorescence, resonance light-scattering, circular dichroism, fourier transform infrared spectroscopy methods and protein-ligand docking. The binding parameters were calculated according to Stern-Volmer equation, and the thermodynamic parameters were determined by the van't Hoff equation. The results indicated that EGCG was capable of binding trypsin and a-chymotrypsin with high affinity, resulting in a change of native conformation of these enzymes. EGCG had a greater influence on the structure of a-chymotrypsin than trypsin. This study can be used to explain the binding interaction mechanism between TP and digestive enzymes.

The Role of Dietary Phenolic Compounds in Protein Digestion and Processing Technologies to Improve Their Antinutritive Properties

“…Naz and others () reported an IC 50 value for chymotrypsin inhibition by EGCG of 46 μM. EGCG was capable of binding α‐chymotrypsin with high affinity (Ka 2.84 × 10 6 at 37 °C), stabilizing chymotrypsin conformation, as evidenced by increased α‐helix and β‐sheet at the expense of decreased random content (Wu and others ). Interestingly, TPs potently and selectively inhibit proteasomal chymotrypsin‐like activity, and therefore the proteasome is regarded as a molecular target of these polyphenols in cancer therapy (Bonfili and others ; Yang and others ).…”

“…The number and position of hydroxyl and aromatic groups, the structure of stereoisomers, and the orientation of catechins in the binding pocket all seem to affect the binding affinity, resulting in the following order of binding affinities: EGCG > ECG > EC > EGC. EGCG binding to trypsin (Ka 1.82 × 10 5 at 37 °C) results in slight protein stabilization with increased β‐sheet and decreased random content (Wu and others ). Quercetin derivatives were found to inhibit trypsin, with quercetin having 10 times higher potency than 4‐guanidinobenzoic acid, the standard serine protease inhibitor (Danihelová and others ).…”

Inhibitory potential of phenylpropanoid glycosides from Ligustrum purpurascens Kudingcha against α‐glucosidase and α‐amylase in vitro

“…For the α‐glucosidase–PPG interaction, the K a values were 1.11 × 10 3 and 2.58 × 10 3 m , respectively, with a mean n value of 0.9. The K a values for most ligand–protein complexes are between 1.0 × 10 3 and 1.0 × 10 5 m (Wu et al ., , ,b,c, ; Yan et al ., ; Fei et al ., ). Therefore, the K a value for the α‐amylase–PPG complex was >1.0 × 10 5 m , for a relatively strong interaction, and the K a value for the α‐glucosidase–PPG complex was nearly 1.0 ×× 10 3 m , for a relatively weak interaction.…”

“…The enzyme-PPG complexes for FTIR were prepared as described (Wu et al, 2013b). In brief, samples of PPGs were incubated for 1 h with enzyme (a-amylase or a-glucosidase) at a PPG:enzyme ratio of 50:1.…”

“…Fourier self-deconvolution and secondary derivative calculations were applied to determine the position and number of component bands. To quantify the area of each component of amide I, a multiple Gaussian curve fitting process based on the above parameters was performed to obtain the relative percentage of secondary structural elements (Dong et al, 1990;Wu et al, 2013b).…”